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This is the least expensive and oldest technology in night vision. All gen 1 intensifier tubes are made in the same factory in the Ukraine, so all Generation 1 Night Vision Devices will have roughly similar performance. (Gen 1+ indicates a current production tube, not a better grade of tube). Only features other than the intensifier tube that affect Gen 1 performance are objective size (large objectives supply more light), magnification (more is NOT better- this is a low resolution product) and the IR illuminator (need by all gen 1 products under tough conditions). If you are using an NIGHT VISION in a marine environment, be sure to use a waterproof model.
Gen 1 units are easily identified. Gen units require 15-30 seconds to power up or power down and will always have some pronounced optical distortion (fish-eye distortion) at the edge of the field.
Gen 1 units can be used to about 75-100 yards to detect man sized objects under average conditions and perhaps a bit more under ideal conditions, say full moonlight. Detection range is defined as the range in which a target will present a recognizable silhouette. Recognition range is defined as the range in which a target begins to show recognizable detail. For most Gen 1 units, this will typically be 50-75 yards or less for a man sized object. It is important to understand that smaller targets will reduce both detection and recognition range.
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The biggest gain in performance occurs between Gen 1 and Gen 2. With a gen 2 tube, you get much reduced distortion at the edge of the field, a screen with better contrast and resolution, better light amplification (less reliance on an IR for supplemental light) ad improved tube life. This all translates into greater range, for both detection and recognition, typically another 50 to 75 yards on both, depending on the grade and type of tube.
Gen 2 also introduces options for grade and type of intensifier tube, though the designation of Gen 2+ indicates a current production tube, not a higher grade of tube. To check performance on a 2nd Generation Night Vision Device, you need to check for both resolution (lp or lpm) and type of tube. Special XD Gen 2 tubes, HDT Gen 2 tubes and SHD3 Gen 2 tubes approach Gen 3 Night Vision Device in performance, but also in price. They truly do bridge the gap between Gen 2 and Gen 3.
The most common measure of tube performance, and one that should always be checked on Gen 2 tubes and higher tubes, is resolution, stated in line pairs per millimeter (lpm) or sometimes just abbreviated as lp. As resolution goes up, so does price.
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This is the highest generation of night vision technology commonly available and the generation currently employed by most military units and other serious users. Generation 3 Night Vision Units, under ideal conditions, are able to detect human sized objects at ranges of two hundred yards or more. As with Gen 2 units, there are many grades and options offered. Gen 3 tubes also offer vastly improved tube life and rarely, if ever, need to be replaced. All Gen 3 units are variations on the original AN PVS-14 (monocular) and AN PVS-7 (bi-ocular goggle) used by the military.
The most common measure of tube performance, and one that should first be checked on a gen 3 units is resolution, stated in line pairs per millimeter (lpm) or sometimes just abbreviated as lp. Other measures used for grading Gen 3 intensifier tubes include signal to noise ratio and screen quality (evenness of brightness and lack of dark spots), though these specifications are seldom listed or stated by manufacturer.
A grading system based on letters is sometimes used as follows for Gen 3. Intensifier tubes designated as Mil-spec must meet minimum military standards for all tube measurements and specifications. Since the origins of NIGHT VISION are military in nature, this is as good as it gets in NIGHT VISION performance. This is also the most expensive and difficult to obtain grade of NIGHT VISION , especially during wartime. Next are tubes that do not meet mil-spec standards. These are typically referred to as commercial grades. A commercial Grade A tube will typically fall short of mil-spec in just one measurement, often with only a minor dark spot on the screen. It may otherwise offer as much resolution as a mil-spec tube. Check the specs. A Grade B commercial tube typically falls short of mil-spec in more than one measurement, though the lower price may make it a good option.
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Night vision technology is about seeing in the dark; it is not about seeing great distances. Simply put, no night vision product (night vision goggles, night vision binoculars, night vision scope, night vision rifle scope, night vision monocular, night vision googles, night vision monoculars) will have the optical resolution of conventional daytime instruments such as binoculars, riflescopes, monoculars and so on. Because of this limit on resolution (screen sharpness), magnification in night vision products is limited, with 5x or 6x being about maximum. The problem, in a nutshell, is that as magnification goes up, image quality in night vision goes down. Excess magnification in this technology degrades the image to the point of being useless. Best image quality in conventional night vision technology is usually obtained at 1x (normal vision, no magnification) to about 3x. Field of view, image steadiness and overall ease of use is also better at these lower magnifications.
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